CVE-2025-39908 net: dev_ioctl: take ops lock in hwtstamp lower paths
A missing lock in Linux kernel hardware timestamping paths can cause a race condition, leading to system warnings and potential denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39908?
CVE-2025-39908 is a high-severity vulnerability in Linux kernel, published on 1 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: dev_ioctl: take ops lock in hwtstamp lower paths
ndo hwtstamp callbacks are expected to run under the per-device ops lock. Make the lower get/set paths consistent with the rest of ndo invocations.
Kernel log: WARNING: CPU: 13 PID: 51364 at ./include/net/netdev_lock.h:70 __netdev_update_features+0x4bd/0xe60 ... RIP: 0010:__netdev_update_features+0x4bd/0xe60 ... Call Trace: <TASK> netdev_update_features+0x1f/0x60 mlx5_hwtstamp_set+0x181/0x290 [mlx5_core] mlx5e_hwtstamp_set+0x19/0x30 [mlx5_core] dev_set_hwtstamp_phylib+0x9f/0x220 dev_set_hwtstamp_phylib+0x9f/0x220 dev_set_hwtstamp+0x13d/0x240 dev_ioctl+0x12f/0x4b0 sock_ioctl+0x171/0x370 __x64_sys_ioctl+0x3f7/0x900 ? __sys_setsockopt+0x69/0xb0 do_syscall_64+0x6f/0x2e0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ... </TASK> .... ---[ end trace 0000000000000000 ]---
Note that the mlx5_hwtstamp_set and mlx5e_hwtstamp_set functions shown in the trace come from an in progress patch converting the legacy ioctl to ndo_hwtstamp_get/set and are not present in mainline.
Which versions are affected by CVE-2025-39908?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-39908?
Apply the vendor's patch.
Is CVE-2025-39908 being exploited?
There is no known exploitation of CVE-2025-39908 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-39908, DEBIAN-CVE-2025-39908, GHSA-qf93-q7mq-9vv4, ROOT-OS-UBUNTU-2204-CVE-2025-39908, ROOT-OS-UBUNTU-2404-CVE-2025-39908, UBUNTU-CVE-2025-39908.